将json字符串从外层到最内层依次连接，平铺成一个List＜String＞

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;

import java.util.ArrayList;
import java.util.List;

public class JSONUtils {

    public static List<String> flattenJson(String jsonString) {
        List<String> flattened = new ArrayList<>();
        flattenJson(JSON.parseObject(jsonString), "", flattened);
        return flattened;
    }

    private static void flattenJson(JSONObject obj, String prefix, List<String> flattened) {
        for (String key : obj.keySet()) {
            Object value = obj.get(key);
            String newPrefix = prefix + key;
            if (value instanceof JSONObject) {
                flattenJson((JSONObject) value, newPrefix + ".", flattened);
            } else if (value instanceof JSONArray) {
                JSONArray arr = (JSONArray) value;
                for (int i = 0; i < arr.size(); i++) {
                    Object arrValue = arr.get(i);
                    if (arrValue instanceof JSONObject) {
                        flattenJson((JSONObject) arrValue, newPrefix + "[" + i + "].", flattened);
                    } else {
                        flattened.add(newPrefix + "[" + i + "]=" + arrValue.toString() + "(" + arrValue.getClass().getSimpleName() + ")");
                    }
                }
            } else {
                flattened.add(newPrefix + "=" + value.toString() + "(" + value.getClass().getSimpleName() + ")");
            }
        }
    }

}